1. Field of the Disclosure
The present disclosure relates generally to image forming devices and more particularly to rotational sensing for a replaceable unit of an image forming device.
2. Description of the Related Art
During the electrophotographic printing process, an electrically charged rotating photoconductive drum is selectively exposed to a laser beam. The areas of the photoconductive drum exposed to the laser beam are discharged creating an electrostatic latent image of a page to be printed on the photoconductive drum. Toner particles are then electrostatically picked up by the latent image on the photoconductive drum creating a toned image on the drum. The toned image is transferred to the print media (e.g., paper) either directly by the photoconductive drum or indirectly by an intermediate transfer member. The toner is then fused to the media using heat and pressure to complete the print.
The image forming device's toner supply is typically stored in one or more replaceable units installed in the image forming device. As these replaceable units run out of toner, the units must be replaced or refilled in order to continue printing. As a result, it is desired to measure the amount of toner remaining in these units in order to warn the user that one of the replaceable units is near an empty state or to prevent printing after one of the units is empty in order to prevent damage to the image forming device. Accordingly, a system for measuring the amount of toner remaining in a replaceable unit of an image forming device is desired.
Further, the replaceable units typically include rotating agitators to fluff and mix the toner. The agitators receive rotational force from a drive element on the exterior of the replaceable unit which, in turn, receives rotational force from a drive motor in the image forming device through a drive transmission that connects the drive motor to the drive element when the replaceable unit is installed in the image forming device. If the drive transmission is disconnected at any point, the drive element of the replaceable unit will not receive rotational force even if the drive motor is operating properly. Accordingly, a system for ensuring that the drive element and agitators are rotating properly is also desired.